Is there a formula for the Vcore voltage?

[Anti]

As in what it should be set to as per the multiplier and the FSB. Or is it all trial and error thrown in with how good your PS is?:confused:

[Wiggo]

It's trail and error depending on several pieces of hardware. Some CPU's will overclock fairly well without the need for extra voltage and some no matter how much ya feed them they'll just refuse to budge plus the same goes for memory. A lot of overclockin' is just plain pure luck for the most of it. Keepin' the whole system cool is another determinin' factor. I like to up both the mem and core voltages by 0.1v before startin' on them.

[Anti]

Thanks for that. Could a windows error BSOD labeling the APU be related to lack of voltage? System @ the time was 2100+@14x166 w/Vcore 1.725 on a 8rda+

[Wiggo]

It's entirely possible but it could also be a product of heat.

[Anti]

Hmm, well I guess here comes the trial part. :cheers:

After thought: Is it a worth wile idea to add a HS to the south bridge?

[Darthtanion]

I haven't been hearing that the chipset of that board are benefiting from added cooling.

[t_wheeler]

How much can I expect the CPU temp to increase for a .1 bump in voltage? A couple degrees? Five? (I have a Barton 2500+ running at 220FSB, 10.5 multiplier, currently at stock voltage.)

[Darthtanion]

I generally use this site to figure processor heat output but they haven't updated to the Barton cores yet. Anyone have anything similar that is up to date?

[t_wheeler]

I just found http://www.digital-daily.com/motherb...on/index04.htm. I don't care for the methodology (I would rather see keeping the FSB and multiplier the same while raising the voltage) but I think the conclusion is fair: If you intend to overclock the processor through raising voltage by over 0.1V, then a full-copper radiator is a must.

Okay, just for kicks I'm going to bump my vCore by .1 and see what it does to the temps. I'll post my results later. (If I don't, it means I burned the CPU up ).

[t_wheeler]

Okay, as promised, my results:

FSB: 220, one case fan
vCore: 1.65 (1.68) -- 79W, 46C
vCore: 1.70 (1.74) -- 84W, 50C

FSB: 225, two case fans
vCore: 1.65 (1.68) -- 81W, 43C
vCore: 1.70 (1.74) -- 87W, 46C

So from these results it appears that the temperature rose by about 8% for a .5v increase. (Or about 4 degrees.)

Note the effect on wattage of going from 220 to 225FSB.

What's most interesting (to me) is the effect of remembering to plug in the second case fan (on the left side of the case). Although the FSB and vCore were both turned up in the second set, the resulting temperature was the same as for the "coolest" FSB/vCore setting.

Based on my minimal Googling, I'm still in the "safe zone" for temps even at 50C. I'd sure like some additional opinions on that though....

BTW, these numbers are all under load: playing a CD, copying a large directory tree on the HDD, and running Sandra's CPU, memory, multi-media and cache burn-in.

Obviously this is very informal and incomplete testing. If I get ambitious I may drop the FSB in 5Mhz increments a few times to get a decent set of numbers.

[Anti]

Hey, thanks for all that info t_wheeler. :thumb: Man you got that fsb up there. Even lowering my multiplier. Mine doesn't like any thing over 166. But then my ram is holding me back there. I hate to see my temps go very far into the 40's under load. It hits about 43c while playing UT2k3 and, that puts 100% load on the cpu. Voltage @ 1.75 (1.82) Even when I turned it up to 1.82 for the 14x I still get BSOD after a while.
Raising the voltage does help increase stability. (If it's an issue) I think I found my Happy Medium for now.
What are you usind to get the wattage reading? :confused:



AMD 2100+ @ 2250Mhz 13.5x166 | Epox 8RDA+
2x256KHX3000 2-2-2-6 @ 333 | AreoFlow TMD
Antec SmartBlue 350watt | 2 TT80mm case fans
Maxtor 60gig | Gigabyte 9000pro 64mgb @ 306/306
1600 for 3Dmark2003 with Vcard @ 317/315

[t_wheeler]

I'm using Sandra3000 to tell me the wattage. No idea if it's accurate -- I'm sure it's just using a formula to calculate, I guess based on vCore and FSB.

If you want to, I think you could probably increase your FSB if you run your memory at 3-3-3-6 instead of 2-2-2-6. I found that memory timing on my box had a huge impact on how high I could clock the FSB. As I recall, at 2.5-3-3-6 I could only run 190Mhz, and 2-3-3-5 required me to step all the way down to 165Mhz.

[Anti]

Yeah, I tried looser timings. Not to much luck. All though the specs say it's good for 370MHZ. Anything over 168 and I'm reseting cmos. So I stuck with the tight timings and low voltage. It is only pc3000. I all ready had 1 stick when I bought the board. So I matched it for the dual channel. I got my eye on the Tyan 9500pro. So I need to put off any other upgrades. Or they'll be imposible to find. Their pretty hard to find now. Thanks for the tip on Sandra. Didn't even think to check that. lol Although I use it for benching.